From 3e914d935960fee25dbe21fbbd2c4ad7ed6f3804 Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 13:36:55 +0000
Subject: [PATCH 01/10] fix: read Blob-backed extension files in diffs

---
 .../diff-view/src/parts/ReadFile/ReadFile.ts  |  9 ++++--
 packages/diff-view/test/ReadFile.test.ts      | 30 +++++++++++++++++++
 packages/e2e/extension/main.js                | 12 ++++++++
 ...iff.extension-blob-file-system-provider.ts | 15 ++++++++++
 4 files changed, 63 insertions(+), 3 deletions(-)
 create mode 100644 packages/e2e/src/diff.extension-blob-file-system-provider.ts

diff --git a/packages/diff-view/src/parts/ReadFile/ReadFile.ts b/packages/diff-view/src/parts/ReadFile/ReadFile.ts
index 0acc1be7..6eeba23b 100644
--- a/packages/diff-view/src/parts/ReadFile/ReadFile.ts
+++ b/packages/diff-view/src/parts/ReadFile/ReadFile.ts
@@ -12,10 +12,13 @@ const readExtensionFile = async (protocol: string, uri: string): Promise<string>
   if (!response.found) {
     throw new Error(`no file system provider found for ${protocol}`)
   }
-  if (typeof response.result !== 'string') {
-    throw new TypeError(`expected file system provider ${protocol} to return a string`)
+  if (typeof response.result === 'string') {
+    return response.result
   }
-  return response.result
+  if (response.result instanceof Blob) {
+    return response.result.text()
+  }
+  throw new TypeError(`expected file system provider ${protocol} to return a string or Blob`)
 }
 
 export const readFile = async (uri: string): Promise<string> => {
diff --git a/packages/diff-view/test/ReadFile.test.ts b/packages/diff-view/test/ReadFile.test.ts
index 3d6ad1fc..e9c17a26 100644
--- a/packages/diff-view/test/ReadFile.test.ts
+++ b/packages/diff-view/test/ReadFile.test.ts
@@ -80,6 +80,36 @@ test('readFile reads extension protocols through extension management worker', a
   ])
 })
 
+test('readFile decodes Blob content from extension file system providers', async (): Promise<void> => {
+  ExtensionManagementWorker.registerMockRpc({
+    'Extensions.executeFileSystemProviderReadFile': async (): Promise<unknown> => ({
+      found: true,
+      result: new Blob(['before 😀\nafter'], { type: 'text/plain' }),
+    }),
+  })
+
+  await expect(readFile('remote-ssh:///workspace/file.txt')).resolves.toBe('before 😀\nafter')
+})
+
+test('readFile returns empty content from an empty Blob extension provider', async (): Promise<void> => {
+  ExtensionManagementWorker.registerMockRpc({
+    'Extensions.executeFileSystemProviderReadFile': async (): Promise<unknown> => ({
+      found: true,
+      result: new Blob([]),
+    }),
+  })
+
+  await expect(readFile('remote-ssh:///workspace/empty.txt')).resolves.toBe('')
+})
+
+test('readFile rejects invalid extension file system provider results', async (): Promise<void> => {
+  ExtensionManagementWorker.registerMockRpc({
+    'Extensions.executeFileSystemProviderReadFile': async (): Promise<unknown> => ({ found: true, result: { content: 'not text' } }),
+  })
+
+  await expect(readFile('remote-ssh:///workspace/file.txt')).rejects.toThrow('expected file system provider remote-ssh to return a string or Blob')
+})
+
 test('readFile rejects when no isolated extension provides the protocol', async (): Promise<void> => {
   ExtensionManagementWorker.registerMockRpc({
     'Extensions.executeFileSystemProviderReadFile': async (): Promise<unknown> => ({ found: false }),
diff --git a/packages/e2e/extension/main.js b/packages/e2e/extension/main.js
index 146af22c..423c31f8 100644
--- a/packages/e2e/extension/main.js
+++ b/packages/e2e/extension/main.js
@@ -3,7 +3,19 @@ const webViewProvider = {
   async create() {},
 }
 
+const fileSystemProvider = {
+  id: 'blob-fixture',
+  async readFile(uri) {
+    if (uri.endsWith('/empty.txt')) {
+      return new Blob([])
+    }
+    return new Blob(['remote 😀 content'])
+  },
+}
+
 export const activate = () => {
   // @ts-ignore
   vscode.registerWebViewProvider(webViewProvider)
+  // @ts-ignore
+  vscode.registerFileSystemProvider(fileSystemProvider)
 }
diff --git a/packages/e2e/src/diff.extension-blob-file-system-provider.ts b/packages/e2e/src/diff.extension-blob-file-system-provider.ts
new file mode 100644
index 00000000..f70c1c88
--- /dev/null
+++ b/packages/e2e/src/diff.extension-blob-file-system-provider.ts
@@ -0,0 +1,15 @@
+import type { Test } from '@lvce-editor/test-with-playwright'
+
+export const name = 'diff.extension-blob-file-system-provider'
+
+export const test: Test = async ({ DiffView, expect, FileSystem, Locator, Workspace }) => {
+  const tmpDir = await FileSystem.getTmpDir()
+  await Workspace.setPath(tmpDir)
+  await DiffView.open('data://before content', 'blob-fixture:///workspace/file.txt')
+
+  const leftRows = Locator('.DiffEditorContentLeft .DiffEditorRows')
+  const rightRows = Locator('.DiffEditorContentRight .DiffEditorRows')
+
+  await expect(leftRows).toHaveText('before content')
+  await expect(rightRows).toHaveText('remote 😀 content')
+}

From 8ffa57ee38d5470b109c12e991b3e24bd1993785 Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 13:40:41 +0000
Subject: [PATCH 02/10] fix: avoid DOM Blob type in diff reader

---
 packages/diff-view/src/parts/ReadFile/ReadFile.ts | 10 +++++++++-
 packages/diff-view/test/ReadFile.test.ts          |  9 +++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/packages/diff-view/src/parts/ReadFile/ReadFile.ts b/packages/diff-view/src/parts/ReadFile/ReadFile.ts
index 6eeba23b..f97c7dc3 100644
--- a/packages/diff-view/src/parts/ReadFile/ReadFile.ts
+++ b/packages/diff-view/src/parts/ReadFile/ReadFile.ts
@@ -7,6 +7,14 @@ interface FileSystemProviderResult {
   readonly result?: unknown
 }
 
+interface BlobLike {
+  readonly text: () => Promise<string>
+}
+
+const isBlobLike = (value: unknown): value is BlobLike => {
+  return typeof value === 'object' && value !== null && Object.prototype.toString.call(value) === '[object Blob]' && 'text' in value && typeof value.text === 'function'
+}
+
 const readExtensionFile = async (protocol: string, uri: string): Promise<string> => {
   const response = (await ExtensionManagementWorker.invoke('Extensions.executeFileSystemProviderReadFile', protocol, uri)) as FileSystemProviderResult
   if (!response.found) {
@@ -15,7 +23,7 @@ const readExtensionFile = async (protocol: string, uri: string): Promise<string>
   if (typeof response.result === 'string') {
     return response.result
   }
-  if (response.result instanceof Blob) {
+  if (isBlobLike(response.result)) {
     return response.result.text()
   }
   throw new TypeError(`expected file system provider ${protocol} to return a string or Blob`)
diff --git a/packages/diff-view/test/ReadFile.test.ts b/packages/diff-view/test/ReadFile.test.ts
index e9c17a26..ab7dc8da 100644
--- a/packages/diff-view/test/ReadFile.test.ts
+++ b/packages/diff-view/test/ReadFile.test.ts
@@ -2,6 +2,11 @@ import { expect, test } from '@jest/globals'
 import { ExtensionManagementWorker, FileSystemWorker, RendererWorker } from '@lvce-editor/rpc-registry'
 import { readFile } from '../src/parts/ReadFile/ReadFile.ts'
 
+const createBlob = (parts: readonly string[]): unknown => {
+  const BlobConstructor = (globalThis as unknown as { readonly Blob: new (parts: readonly string[]) => unknown }).Blob
+  return new BlobConstructor(parts)
+}
+
 test('readFile returns empty content for untitled uri', async (): Promise<void> => {
   const result = await readFile('untitled://Untitled-1')
 
@@ -84,7 +89,7 @@ test('readFile decodes Blob content from extension file system providers', async
   ExtensionManagementWorker.registerMockRpc({
     'Extensions.executeFileSystemProviderReadFile': async (): Promise<unknown> => ({
       found: true,
-      result: new Blob(['before 😀\nafter'], { type: 'text/plain' }),
+      result: createBlob(['before 😀\nafter']),
     }),
   })
 
@@ -95,7 +100,7 @@ test('readFile returns empty content from an empty Blob extension provider', asy
   ExtensionManagementWorker.registerMockRpc({
     'Extensions.executeFileSystemProviderReadFile': async (): Promise<unknown> => ({
       found: true,
-      result: new Blob([]),
+      result: createBlob([]),
     }),
   })
 

From 582376df723ee48d39ebb5ce1511388e65999f11 Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 13:46:59 +0000
Subject: [PATCH 03/10] test: declare Blob fixture file system provider

---
 packages/e2e/extension/extension.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/e2e/extension/extension.json b/packages/e2e/extension/extension.json
index 5504e052..9d267a85 100644
--- a/packages/e2e/extension/extension.json
+++ b/packages/e2e/extension/extension.json
@@ -1,6 +1,7 @@
 {
   "name": "diff-view-e2e",
-  "activation": ["onWebView:diff-prototype"],
+  "activation": ["onWebView:diff-prototype", "onFileSystem:blob-fixture"],
+  "fileSystemProviders": [{ "id": "blob-fixture" }],
   "browser": "main.js",
   "contentSecurityPolicy": ["default-src 'none'", "script-src 'self'"],
   "rpc": [

From 7f59c3228ea721634b928751e706af7b1207592b Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 13:53:34 +0000
Subject: [PATCH 04/10] test: isolate Blob filesystem fixture

---
 packages/e2e/extension/extension.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/e2e/extension/extension.json b/packages/e2e/extension/extension.json
index 9d267a85..f22c2114 100644
--- a/packages/e2e/extension/extension.json
+++ b/packages/e2e/extension/extension.json
@@ -1,5 +1,6 @@
 {
   "name": "diff-view-e2e",
+  "isolated": true,
   "activation": ["onWebView:diff-prototype", "onFileSystem:blob-fixture"],
   "fileSystemProviders": [{ "id": "blob-fixture" }],
   "browser": "main.js",

From 1a33afa295c251823f3c141e4ece3a9036793e03 Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 14:11:12 +0000
Subject: [PATCH 05/10] Fix isolated Blob filesystem e2e fixture

---
 package-lock.json                         | 27 ++++++++++++++++++++++-
 package.json                              |  5 +++++
 packages/e2e/extension/main.js            |  8 ++++---
 packages/e2e/package.json                 | 17 ++++++++------
 packages/e2e/scripts/prepare-extension.js | 21 ++++++++++++++++++
 5 files changed, 67 insertions(+), 11 deletions(-)
 create mode 100644 packages/e2e/scripts/prepare-extension.js

diff --git a/package-lock.json b/package-lock.json
index b9518fcb..b7c33a84 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -2891,6 +2891,29 @@
       "license": "MIT",
       "optional": true
     },
+    "node_modules/@lvce-editor/api": {
+      "version": "8.84.0",
+      "resolved": "https://registry.npmjs.org/@lvce-editor/api/-/api-8.84.0.tgz",
+      "integrity": "sha512-7Zck/G4gOz75lw25KHNuI3YPSjEPRgrYeMlWnWkSNph7Gi8oxPFiE3LLTnF8Ip7Xd2qkWk45LqulUmo68yRU4Q==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lvce-editor/command": "^2.0.0",
+        "@lvce-editor/rpc": "^6.4.0",
+        "@lvce-editor/rpc-registry": "^9.24.0",
+        "@lvce-editor/virtual-dom-worker": "^10.0.0"
+      }
+    },
+    "node_modules/@lvce-editor/api/node_modules/@lvce-editor/virtual-dom-worker": {
+      "version": "10.2.0",
+      "resolved": "https://registry.npmjs.org/@lvce-editor/virtual-dom-worker/-/virtual-dom-worker-10.2.0.tgz",
+      "integrity": "sha512-URtDWcAFadP7SLOqfepRxomJmNRQDmON8GFKRfsA1dOgcqBnoBR4G5xwo6oDeZvP4pnRAzHR3QB3b8I6nASU+w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@lvce-editor/constants": "^5.14.0"
+      }
+    },
     "node_modules/@lvce-editor/assert": {
       "version": "1.9.0",
       "resolved": "https://registry.npmjs.org/@lvce-editor/assert/-/assert-1.9.0.tgz",
@@ -15808,7 +15831,9 @@
       "version": "0.0.0-dev",
       "license": "MIT",
       "devDependencies": {
-        "@lvce-editor/test-with-playwright": "^22.29.0"
+        "@lvce-editor/api": "^8.84.0",
+        "@lvce-editor/test-with-playwright": "^22.29.0",
+        "esbuild": "^0.28.2"
       }
     },
     "packages/server": {
diff --git a/package.json b/package.json
index f8a80323..8460f6fb 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,11 @@
     "trigger-ci-branches": "bash packages/build/trigger-ci-branches.sh",
     "type-check": "tsc -b"
   },
+  "knip": {
+    "ignoreDependencies": [
+      "@lvce-editor/api"
+    ]
+  },
   "prettier": {
     "semi": false,
     "singleQuote": true,
diff --git a/packages/e2e/extension/main.js b/packages/e2e/extension/main.js
index 423c31f8..aa8718cd 100644
--- a/packages/e2e/extension/main.js
+++ b/packages/e2e/extension/main.js
@@ -1,3 +1,5 @@
+import { activate as activateExtensionApi, registerFileSystemProvider } from '@lvce-editor/api'
+
 const webViewProvider = {
   id: 'diff-prototype',
   async create() {},
@@ -13,9 +15,9 @@ const fileSystemProvider = {
   },
 }
 
-export const activate = () => {
+export const activate = async () => {
+  await activateExtensionApi()
   // @ts-ignore
   vscode.registerWebViewProvider(webViewProvider)
-  // @ts-ignore
-  vscode.registerFileSystemProvider(fileSystemProvider)
+  registerFileSystemProvider(fileSystemProvider)
 }
diff --git a/packages/e2e/package.json b/packages/e2e/package.json
index 8c8f0661..470a52fb 100644
--- a/packages/e2e/package.json
+++ b/packages/e2e/package.json
@@ -5,15 +5,18 @@
   "type": "module",
   "main": "index.js",
   "scripts": {
-    "e2e": "test-with-playwright --only-extension=. --test-path=. --reuse-page",
-    "e2e:firefox": "test-with-playwright --only-extension=. --test-path=. --browser=firefox --reuse-page",
-    "e2e:firefox:headless": "test-with-playwright --only-extension=. --test-path=. --browser=firefox --headless --reuse-page",
-    "e2e:headless": "test-with-playwright --only-extension=. --test-path=. --headless --reuse-page",
-    "e2e:webkit": "test-with-playwright --only-extension=. --test-path=. --browser=webkit --reuse-page",
-    "e2e:webkit:headless": "test-with-playwright --only-extension=. --test-path=. --browser=webkit --headless --reuse-page",
+    "e2e": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --reuse-page",
+    "e2e:firefox": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=firefox --reuse-page",
+    "e2e:firefox:headless": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=firefox --headless --reuse-page",
+    "e2e:headless": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --headless --reuse-page",
+    "e2e:prepare": "node ./scripts/prepare-extension.js",
+    "e2e:webkit": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=webkit --reuse-page",
+    "e2e:webkit:headless": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=webkit --headless --reuse-page",
     "type-check": "tsc"
   },
   "devDependencies": {
-    "@lvce-editor/test-with-playwright": "^22.29.0"
+    "@lvce-editor/api": "^8.84.0",
+    "@lvce-editor/test-with-playwright": "^22.29.0",
+    "esbuild": "^0.28.2"
   }
 }
diff --git a/packages/e2e/scripts/prepare-extension.js b/packages/e2e/scripts/prepare-extension.js
new file mode 100644
index 00000000..496a1131
--- /dev/null
+++ b/packages/e2e/scripts/prepare-extension.js
@@ -0,0 +1,21 @@
+import { cp, mkdir, rm } from 'node:fs/promises'
+import { dirname, join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { build } from 'esbuild'
+
+const packageRoot = join(dirname(fileURLToPath(import.meta.url)), '..')
+const temporaryDirectory = join(packageRoot, '.tmp')
+const outputDirectory = join(temporaryDirectory, 'extension')
+
+await rm(temporaryDirectory, { force: true, recursive: true })
+await mkdir(outputDirectory, { recursive: true })
+
+await cp(join(packageRoot, 'extension', 'extension.json'), join(outputDirectory, 'extension.json'))
+await build({
+  bundle: true,
+  entryPoints: [join(packageRoot, 'extension', 'main.js')],
+  external: ['electron', 'node:*'],
+  format: 'esm',
+  outfile: join(outputDirectory, 'main.js'),
+  platform: 'browser',
+})

From 7fe19b1cf53760751b3030e7de7a88b321e92ccd Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 14:35:08 +0000
Subject: [PATCH 06/10] Keep e2e extension root when bundling

---
 packages/e2e/extension/extension.json     |  2 +-
 packages/e2e/package.json                 | 12 ++++++------
 packages/e2e/scripts/prepare-extension.js | 12 +++++-------
 3 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/packages/e2e/extension/extension.json b/packages/e2e/extension/extension.json
index f22c2114..383d5249 100644
--- a/packages/e2e/extension/extension.json
+++ b/packages/e2e/extension/extension.json
@@ -3,7 +3,7 @@
   "isolated": true,
   "activation": ["onWebView:diff-prototype", "onFileSystem:blob-fixture"],
   "fileSystemProviders": [{ "id": "blob-fixture" }],
-  "browser": "main.js",
+  "browser": ".tmp/main.js",
   "contentSecurityPolicy": ["default-src 'none'", "script-src 'self'"],
   "rpc": [
     {
diff --git a/packages/e2e/package.json b/packages/e2e/package.json
index 470a52fb..64bf3b62 100644
--- a/packages/e2e/package.json
+++ b/packages/e2e/package.json
@@ -5,13 +5,13 @@
   "type": "module",
   "main": "index.js",
   "scripts": {
-    "e2e": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --reuse-page",
-    "e2e:firefox": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=firefox --reuse-page",
-    "e2e:firefox:headless": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=firefox --headless --reuse-page",
-    "e2e:headless": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --headless --reuse-page",
+    "e2e": "npm run e2e:prepare && test-with-playwright --only-extension=. --test-path=. --reuse-page",
+    "e2e:firefox": "npm run e2e:prepare && test-with-playwright --only-extension=. --test-path=. --browser=firefox --reuse-page",
+    "e2e:firefox:headless": "npm run e2e:prepare && test-with-playwright --only-extension=. --test-path=. --browser=firefox --headless --reuse-page",
+    "e2e:headless": "npm run e2e:prepare && test-with-playwright --only-extension=. --test-path=. --headless --reuse-page",
     "e2e:prepare": "node ./scripts/prepare-extension.js",
-    "e2e:webkit": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=webkit --reuse-page",
-    "e2e:webkit:headless": "npm run e2e:prepare && test-with-playwright --only-extension=./.tmp/extension --test-path=. --browser=webkit --headless --reuse-page",
+    "e2e:webkit": "npm run e2e:prepare && test-with-playwright --only-extension=. --test-path=. --browser=webkit --reuse-page",
+    "e2e:webkit:headless": "npm run e2e:prepare && test-with-playwright --only-extension=. --test-path=. --browser=webkit --headless --reuse-page",
     "type-check": "tsc"
   },
   "devDependencies": {
diff --git a/packages/e2e/scripts/prepare-extension.js b/packages/e2e/scripts/prepare-extension.js
index 496a1131..f677a2c6 100644
--- a/packages/e2e/scripts/prepare-extension.js
+++ b/packages/e2e/scripts/prepare-extension.js
@@ -1,21 +1,19 @@
-import { cp, mkdir, rm } from 'node:fs/promises'
+import { mkdir, rm } from 'node:fs/promises'
 import { dirname, join } from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { build } from 'esbuild'
 
 const packageRoot = join(dirname(fileURLToPath(import.meta.url)), '..')
-const temporaryDirectory = join(packageRoot, '.tmp')
-const outputDirectory = join(temporaryDirectory, 'extension')
+const extensionDirectory = join(packageRoot, 'extension')
+const temporaryDirectory = join(extensionDirectory, '.tmp')
 
 await rm(temporaryDirectory, { force: true, recursive: true })
-await mkdir(outputDirectory, { recursive: true })
-
-await cp(join(packageRoot, 'extension', 'extension.json'), join(outputDirectory, 'extension.json'))
+await mkdir(temporaryDirectory, { recursive: true })
 await build({
   bundle: true,
   entryPoints: [join(packageRoot, 'extension', 'main.js')],
   external: ['electron', 'node:*'],
   format: 'esm',
-  outfile: join(outputDirectory, 'main.js'),
+  outfile: join(temporaryDirectory, 'main.js'),
   platform: 'browser',
 })

From fe4909dfb7c2ab6b8920bc9fc4c821ad2c275712 Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 14:45:23 +0000
Subject: [PATCH 07/10] Report Blob provider errors in e2e regression

---
 packages/e2e/src/diff.extension-blob-file-system-provider.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/e2e/src/diff.extension-blob-file-system-provider.ts b/packages/e2e/src/diff.extension-blob-file-system-provider.ts
index f70c1c88..1586865e 100644
--- a/packages/e2e/src/diff.extension-blob-file-system-provider.ts
+++ b/packages/e2e/src/diff.extension-blob-file-system-provider.ts
@@ -8,8 +8,8 @@ export const test: Test = async ({ DiffView, expect, FileSystem, Locator, Worksp
   await DiffView.open('data://before content', 'blob-fixture:///workspace/file.txt')
 
   const leftRows = Locator('.DiffEditorContentLeft .DiffEditorRows')
-  const rightRows = Locator('.DiffEditorContentRight .DiffEditorRows')
+  const rightRowsOrError = Locator('.DiffEditorContentRight .DiffEditorRows, .DiffEditorContentRight .DiffEditorErrorMessage')
 
   await expect(leftRows).toHaveText('before content')
-  await expect(rightRows).toHaveText('remote 😀 content')
+  await expect(rightRowsOrError).toHaveText('remote 😀 content')
 }

From 91ff87edfdbf534e408e81976573e22343a11590 Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 14:54:19 +0000
Subject: [PATCH 08/10] Register isolated file system fixture at startup

---
 packages/e2e/extension/main.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/e2e/extension/main.js b/packages/e2e/extension/main.js
index aa8718cd..56702275 100644
--- a/packages/e2e/extension/main.js
+++ b/packages/e2e/extension/main.js
@@ -15,9 +15,11 @@ const fileSystemProvider = {
   },
 }
 
-export const activate = async () => {
+const main = async () => {
   await activateExtensionApi()
   // @ts-ignore
   vscode.registerWebViewProvider(webViewProvider)
   registerFileSystemProvider(fileSystemProvider)
 }
+
+main().catch(console.error)

From e6e065373e8d80826131dc306cb611f1632f7e54 Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 15:05:13 +0000
Subject: [PATCH 09/10] Add test extension manifest id

---
 packages/e2e/extension/extension.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/e2e/extension/extension.json b/packages/e2e/extension/extension.json
index 383d5249..8179b9f1 100644
--- a/packages/e2e/extension/extension.json
+++ b/packages/e2e/extension/extension.json
@@ -1,4 +1,5 @@
 {
+  "id": "test.diff-view-e2e",
   "name": "diff-view-e2e",
   "isolated": true,
   "activation": ["onWebView:diff-prototype", "onFileSystem:blob-fixture"],

From 79adeb75cdd29155d7cefabd3e8cdf1295fe24db Mon Sep 17 00:00:00 2001
From: levivilet <72156503+levivilet@users.noreply.github.com>
Date: Wed, 23 Sep 2026 15:16:30 +0000
Subject: [PATCH 10/10] fix: register Blob diff fixture with web extension
 registry

---
 packages/e2e/extension/extension.json          |  7 ++-----
 packages/e2e/extension/main.js                 | 18 +-----------------
 .../fixtures/blob-file-system/extension.json   | 10 ++++++++++
 packages/e2e/fixtures/blob-file-system/main.js | 18 ++++++++++++++++++
 packages/e2e/scripts/prepare-extension.js      |  4 ++--
 ...diff.extension-blob-file-system-provider.ts |  3 ++-
 6 files changed, 35 insertions(+), 25 deletions(-)
 create mode 100644 packages/e2e/fixtures/blob-file-system/extension.json
 create mode 100644 packages/e2e/fixtures/blob-file-system/main.js

diff --git a/packages/e2e/extension/extension.json b/packages/e2e/extension/extension.json
index 8179b9f1..5504e052 100644
--- a/packages/e2e/extension/extension.json
+++ b/packages/e2e/extension/extension.json
@@ -1,10 +1,7 @@
 {
-  "id": "test.diff-view-e2e",
   "name": "diff-view-e2e",
-  "isolated": true,
-  "activation": ["onWebView:diff-prototype", "onFileSystem:blob-fixture"],
-  "fileSystemProviders": [{ "id": "blob-fixture" }],
-  "browser": ".tmp/main.js",
+  "activation": ["onWebView:diff-prototype"],
+  "browser": "main.js",
   "contentSecurityPolicy": ["default-src 'none'", "script-src 'self'"],
   "rpc": [
     {
diff --git a/packages/e2e/extension/main.js b/packages/e2e/extension/main.js
index 56702275..146af22c 100644
--- a/packages/e2e/extension/main.js
+++ b/packages/e2e/extension/main.js
@@ -1,25 +1,9 @@
-import { activate as activateExtensionApi, registerFileSystemProvider } from '@lvce-editor/api'
-
 const webViewProvider = {
   id: 'diff-prototype',
   async create() {},
 }
 
-const fileSystemProvider = {
-  id: 'blob-fixture',
-  async readFile(uri) {
-    if (uri.endsWith('/empty.txt')) {
-      return new Blob([])
-    }
-    return new Blob(['remote 😀 content'])
-  },
-}
-
-const main = async () => {
-  await activateExtensionApi()
+export const activate = () => {
   // @ts-ignore
   vscode.registerWebViewProvider(webViewProvider)
-  registerFileSystemProvider(fileSystemProvider)
 }
-
-main().catch(console.error)
diff --git a/packages/e2e/fixtures/blob-file-system/extension.json b/packages/e2e/fixtures/blob-file-system/extension.json
new file mode 100644
index 00000000..b8f5c92b
--- /dev/null
+++ b/packages/e2e/fixtures/blob-file-system/extension.json
@@ -0,0 +1,10 @@
+{
+  "id": "test.blob-file-system",
+  "isolated": true,
+  "fileSystemProviders": [
+    {
+      "id": "blob-fixture"
+    }
+  ],
+  "browser": ".tmp/main.js"
+}
diff --git a/packages/e2e/fixtures/blob-file-system/main.js b/packages/e2e/fixtures/blob-file-system/main.js
new file mode 100644
index 00000000..e3464c4f
--- /dev/null
+++ b/packages/e2e/fixtures/blob-file-system/main.js
@@ -0,0 +1,18 @@
+import { activate as activateExtensionApi, registerFileSystemProvider } from '@lvce-editor/api'
+
+const fileSystemProvider = {
+  id: 'blob-fixture',
+  async readFile(uri) {
+    if (uri.endsWith('/empty.txt')) {
+      return new Blob([])
+    }
+    return new Blob(['remote 😀 content'])
+  },
+}
+
+const main = async () => {
+  await activateExtensionApi()
+  registerFileSystemProvider(fileSystemProvider)
+}
+
+main().catch(console.error)
diff --git a/packages/e2e/scripts/prepare-extension.js b/packages/e2e/scripts/prepare-extension.js
index f677a2c6..d8a6c164 100644
--- a/packages/e2e/scripts/prepare-extension.js
+++ b/packages/e2e/scripts/prepare-extension.js
@@ -4,14 +4,14 @@ import { fileURLToPath } from 'node:url'
 import { build } from 'esbuild'
 
 const packageRoot = join(dirname(fileURLToPath(import.meta.url)), '..')
-const extensionDirectory = join(packageRoot, 'extension')
+const extensionDirectory = join(packageRoot, 'fixtures', 'blob-file-system')
 const temporaryDirectory = join(extensionDirectory, '.tmp')
 
 await rm(temporaryDirectory, { force: true, recursive: true })
 await mkdir(temporaryDirectory, { recursive: true })
 await build({
   bundle: true,
-  entryPoints: [join(packageRoot, 'extension', 'main.js')],
+  entryPoints: [join(extensionDirectory, 'main.js')],
   external: ['electron', 'node:*'],
   format: 'esm',
   outfile: join(temporaryDirectory, 'main.js'),
diff --git a/packages/e2e/src/diff.extension-blob-file-system-provider.ts b/packages/e2e/src/diff.extension-blob-file-system-provider.ts
index 1586865e..9bcfd00f 100644
--- a/packages/e2e/src/diff.extension-blob-file-system-provider.ts
+++ b/packages/e2e/src/diff.extension-blob-file-system-provider.ts
@@ -2,9 +2,10 @@ import type { Test } from '@lvce-editor/test-with-playwright'
 
 export const name = 'diff.extension-blob-file-system-provider'
 
-export const test: Test = async ({ DiffView, expect, FileSystem, Locator, Workspace }) => {
+export const test: Test = async ({ DiffView, expect, Extension, FileSystem, Locator, Workspace }) => {
   const tmpDir = await FileSystem.getTmpDir()
   await Workspace.setPath(tmpDir)
+  await Extension.addWebExtension(import.meta.resolve('../fixtures/blob-file-system'))
   await DiffView.open('data://before content', 'blob-fixture:///workspace/file.txt')
 
   const leftRows = Locator('.DiffEditorContentLeft .DiffEditorRows')